Orpheus10,
There is a slight difference in the pronunciation of TEEL and TEAL but it would take a trained ear (like that of an actor or someone for who English is/was a second language).
TEEL has a long 'e' and TEAL has a long 'e' with a soft 'a'.
It would be like saying MERRY, MARRY and MARY. There is a difference if you were to strive to pronounce them the way they are spelt.
I know it sounds like splitting hairs (hares) but I remember this from some college course.